NIR- SERS spectra were measured for the neurotransmitters dopamine and norepinephrine at concentrations between 5x10-6 and 5x10-9 M in colloidal silver solutions with accumulation times between 0.025 and 1 second. The low concentrations and fast acquisition are in the order of physiologically relevant concentrations and close to the time scale of neuronal processes, respectively. Our results demonstrate the potential of NIR-SERS in probing dopamine and norepinephrine with high sensitivity and specificity and suggest NIR-SERS on colloidal silver as a powerful tool to study neurotransmitters in brain extracts and dialysates.